BSU researcher studies impact of forward-facing sonar on elusive muskie

BEMIDJI — Muskies are known as the fish of 10,000 casts, because the elusive creatures are notoriously hard to catch.

But Bemidji State University graduate student Baylor Short knows dozens of the muskies in Leech Lake — some even by name.

“We've got one that we called Lil Finna, and it was a fish that traveled vast parts of the lake … We found him here one day, and then two weeks later, he's 7 miles away in a different spot,” Short said.

Short is part of a team studying if and how fishing increases muskie stress and deaths — and how technology that makes catching muskies easier adds to the issue.

The research project came about after anglers expressed concern that new advances in fishing technology could be causing fish to die.

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The main concern: forward-facing sonar. This technology can map out the once-elusive muskies in real time on a screen, like a video game showing anglers exactly when and where to drop their bait.

The issue sparked a collaborative project between fishing advocacy and conservation organization MN-FISH, the Minnesota Department of Natural Resources, Leech Lake Band of Ojibwe, Muskies Inc. and BSU.

Muskellunge, known popularly as muskies, are only found in around 100 of Minnesota's thousands of lakes. Roughly half of those populations were introduced through DNR stocking. The Leech Lake population serves as broodstock for these stocking efforts.

BSU Biology Professor Andy Hafs is Short’s adviser. He said the use of front-facing sonar means muskies can even be fished in deep water during a period when they should be resting and recovering after spawning.

“You find one that's chilling out down 40 feet, and you can drop a jig right down in front of its face, and it'll snap on it. Whereas in years past we wouldn't have been able to do that type of thing. We might not have even known they were there,” Hafs said.

At these depths, pressure changes are one potential stressor in the fishing process. The fish have some anatomical tricks to manage changes in barometric pressure, but muskies are reeled in from deep water to the lake’s surface much faster than they’d swim on their own. Like scuba divers experiencing injury from surfacing too fast, this could be causing harm to the fish.

These huge fish also don’t willingly hop into the arms of the people catching them. They tend to put up a fight, thrashing around. That can also cause harm. And with better technology, muskies could go through the stress of being caught more often.

“A fish that maybe was caught once, twice, three times in its life or never now might be caught multiple times in a year, just because the anglers are so much better at catching the fish than they were,” Hafs said.

Hafs knew someone who would make a great fit for the muskie research ahead.

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“I knew a past student, Baylor Short, that lived in the area and knew Leech Lake really, really well, knew how to muskie fish really well, which would be important for this project,” Hafs said.

Short was able to join the team as a graduate student while also remaining a fisheries specialist with the Leech Lake Band of Ojibwe.

The researchers catch the fish in two ways: by using a hook and line, and with a structured net trap called a fyke net. They quickly implant acoustic tags into the fish and then release them.

“We're looking at two minutes max, minute and a half. It's quite a quick operation,” Short said. The tags emit signals that can be picked up by receivers within about 750 meters of the fish. “They're pretty sweet. They tell us the depth that the fish are sitting at, the temperature that the fish are sitting at,” Short said.

The researchers then monitor the tagged fish to see whether fished and net-caught muskies die at different rates. In the meantime, the tags provide a wealth of information about how the muskies use their habitat and where they travel.

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“Are these fish setting up a home range? Are they sitting in one spot for most of the year, or are they, you know, cruising around all over the lake?” Short said.

Short and his colleagues can scan for a designated fish’s frequency when they’re out on the water. They also rely on passive receivers, which remain in the water and record data on nearby fish 24/7.

Short said he spends a couple hundred days of the year out on the water catching, tagging and collecting data on the muskies. In that time, he’s encountered some of the same fish over and over again. He even has some favorites.

One is a 32-inch male named Shorty that the team tagged in the spring of last year. This muskie is a bit of a homebody, staying in one small area for months, which proved surprisingly useful for the team.

“If we were ever having a bad day out on the lake and we weren't finding any fish, we were able to go back and look for Shorty, and we could usually find him. And it just gave us that little bit of confidence boost that you know the equipment's still working,” Short said.

Short said previous studies suggest muskies tend to behave this way — staying in one area for the summer. But the team is learning that’s not always the case.

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“It's interesting to see that some of our fish don't really do that. They'll post up in a spot for a couple days, and then all of a sudden, they're on vacation. They want to go somewhere else for a while,” Short said.

Lil Finna is one of those fish. In the span of only a few weeks, the fish pinged receivers miles apart. As the project continues, the team will learn more about how muskies are responding to technology.

“This is a really neat species that we're learning about. And although we have one primary objective that was the reason the grant was funded, we're going to learn so much more than that,” Hafs said.

For Short, the work feels rewarding in a full-circle way.

“Being able to work with a fish that, growing up, held a special place in my eyes or my heart more or less, to continue and see like, ‘OK, hey like I might be able to do something for the better of this population or the better of this species,’ was really awesome,” Short said.

Stella Mayerhoff is a Report for America corps member, covering Minnesota’s headwaters region for KAXE in Grand Rapids, Minnesota. Report for America places talented journalists in local newsrooms to report on under-covered issues and regions.